CRUSTACEA, 995 
other leg bears an obtuse tooth at the anterior margin. 
The wrist is still a little shorter than the length of the 
cephalothorax, it is namely 5 millim. long and scarcely 2 
millim. broad in the middle and consequently has the same 
form as in the african species; the rather acute and straight 
anterior margin presents only one single small ob- 
tuse tooth at the proximal end, though it projects a lit- 
tle near the distal end; the posterior margin terminates at 
the distal end into a rather acute tooth , that is not preceded , 
however, by a small tubercle. The upper surface of the wrist 
is marked with a rather deep longitudinal groove, near 
and parallel with the anterior margin; it is not granulate, 
but provided with some elevated lines towards the poste- 
rior border. The chela resembles the left chela of Petrol. 
mosssambicus (Hilgendorf, 1e. fig. 6); it is 10 millim. 
long and 4*/, millim. broad, therefore nearly twice as long 
as broad. The much flattened palm is slightly obtusely 
cristate near the straight inner margin and the outer 
margin is very sharp, a little arcuate and entire, The upper 
surface is not tubercular, and, like the under surface, 
almost smooth. The fingers seem to be pubescent on the 
inner border and a short pubescence seems to have been 
present also at the under surface of the outer margin of 
the palm, but the long hairs of Petrol. mossambicus are 
deficient. 
The ambulatory legs that are not hairy, have still a 
little more compressed shape than those of Petrol. mos- 
sambicus. The anterior margin of the meropodites is sharply 
carinate, here and there granulate, but not dentate; on 
the same manner the posterior margin is unarmed, but 
somewhat granular in the first and second pair. The outer 
surface of these joints is granulate and rather deeply 
suleate almost in the middle, especially that of the me- 
ropodites of the second and third pair. The anterior margin 
of the carpopodites is also carinate and these joints are, 
like the propodites, somewhat granular; the outer surface 
finally of the last pair of legs is also granular. 
Notes from the Leyden Museum, Vol. XV. 
